1. Field of the Invention
The present invention relates to a method and an apparatus for reading bar codes.
In recent years, information input using bar codes are widely used for registering and settling the account for commodities purchased by customers in shops as well as for the commodity and product management in warehouses and distribution areas.
2. Description of the Related Art
Various bar codes are in use now for different applications. If a bar code reader can meet the requirements of only a specific type of bar code, it cannot accommodate a plurality of types of bar code which may be required to be read in shops and warehouses. Installation of a plurality of bar code readers which would be required to meet this requirement would accompany an added installation cost and space. Also, installation of a plurality of bar code readers in such a case has no practical value.
In view of this fact, a single bar code reader can desirably read a plurality of types of bar codes which may be attached to commodities and articles.
Since various bar codes have different methods of recording numerical values and characters, however, the demodulation for reproducing numerical values and the like from a bar code requires a processing method corresponding to that of the particular bar code.
A bar code of any type has a feature (partition) specific to the particular bar code type. For this reason, determining the type of a bar code which has been read requires a search for the feature of each bar code type. Depending on the manner in which a bar code is read, however, a bar code configuration analogous to the type b in features may be read when the bar code of type a is actually being read. In such a case, the demodulation is performed for the type b the bar code, and the bar code a cannot be demodulated, thereby leading to a read error.